Used motor not running when bought how to fix?

[Redcatdaddy84]

i recently bought a duratrax evader st nitro used. The guy said it would run when i put a new pull start on it. I of course did and the thing didn't fire. I check glow plug it was good, used my own igniter. he had fuel in the tank but who knows how old so i cleared it out and put fresh in primed engine nothing. engine has decent compression just wondering what to try next. Thanks for any info

 

[3_Stroke_Motor]

check the idle speed screw, to do this, cut a slit in an old credit card, hotel card or somthing of the nature and stick in the venturi and close the body and align the plate up to the card. That is a good width to use for the idle speed. Are you getting fuel into the engine? take some clean fuel tubing and blow into the carb to clear any debris that may be blocking fuel. Is your glow ignitor fully charged? The plug may glow, but might not be enough to spark the fuel. Are you using good fuel? Get a new quart and try that. Reset the tuning screws to stock. You should be able to find the stock settings online, but there are guidelines to go by to reset it. For most carbs, I think 3 1/2 turns from close to 4 1/2 is stock, and the low end youll need to get some clean fuel tubing. Close the LSN all the way. Blow on the line going into the carb while opening the LSN. Continue opening until you can feel or hear air flowing into the carb. This should reset it close to factory. Do you have good seals? Check all seals on the engine. Check to make sure your heat sink is firmly tightened and loc tightened (blue hi temp only!) Check your seal on the back plate where your pull starter is bolted on. If this plate it not tightened it may cause it no to fire. Try a new glow plug, even though the plug ignites, it may be still be bad. (check for a cylindrical coil on the element in the plug) and make sure there are not deposits on the coil. This may cause the inability to start. Disassemble the engine and check for worn, rusted or even broken parts such as a worn wrist pin, scratched sleeve or a piston with a lot of deposits on it. Go down to your local auto parts store and buy "Carb and Throttle Body Cleaner" this is a highly volatile engine cleaner used to remove deposits from throttle bodies on cars, but it works excellent when cleaning a nitro engine to remove those pesky carbon deposits from the piston and crankcase. Reassemble the engine and loctite all screws to ensure a good seal. BUt dont tear down your engine unless all of the above fails to start the engine. I may be forgetting something, but these are the main reasons to cause problems. If all else fails, this may be the reason he sold it to you without a pull start, because he didn't want to show you it wouldn't start! Never buy a used engine without first hearing it sing (idle) for a minute and rev up to close max RPM! THESE ARE MUSTS WHEN BUYING A USED NITRO RIG!You may have gotten burned, and it may be a costly rebuild, or replacement. (in some cases a rebuild costs more than the engine itself)

if it comes down to it, watch these videos while your tearing down your engine, this guy has an excellent walk through on how to inspect your engine for worn parts and ones that may need to be replaced.

[ame="http://www.youtube.com/watch?v=7StsUUesEw8&feature=relmfu"]RC Nitro Engine Rebuild Pt 1 Complete Engine Tear Down - YouTube[/ame]
[ame="http://www.youtube.com/watch?v=7iLOe__2bJE"]RC Nitro Engine Rebuild Pt 2 Nitro Engine Inspection - YouTube[/ame]
[ame="http://www.youtube.com/watch?v=K93yVGcevd0&feature=fvwrel"]RC Nitro Engine Rebuild Pt 3 Cleaning Your Nitro Engine - YouTube[/ame]
[ame="http://www.youtube.com/watch?v=gWDb43LLA5g&feature=fvwrel"]RC Nitro Engine Rebuild Pt 4 Bearing Replacement - YouTube[/ame]
[ame="http://www.youtube.com/watch?v=xf38gMtMHfI&feature=relmfu"]RC Nitro Engine Rebuild Pt 5 Nitro RC Engine Assembly - YouTube[/ame]

this guy, alishanmao, also has good videos on beginners problem with nitro engines. he may not use quality rigs for his vids, but it is universal.

[ame="http://www.youtube.com/watch?v=gKVSB-NV_D4"]Beginner Nitro Engine Issues n how to fix them - YouTube[/ame]

---------- Post added at 11:59 AM ---------- Previous post was at 11:56 AM ----------

assuming your a beginner, it may be wise to invest in a roto start for tuning and trouble shooting, it will prevent you from yanking your arm off and getting blisters in between your fingers.

 

[Nitro New Guy]

Great helpful popst BRAVO to you " 3 Stroke Motor " Great video also.

 

[SSX]

Just WOW, what an answer dude, great advice/info.

 

[Zdragon71]

Nice! Responses like that one are the reason RCNT is the best forum for rc troubles.

 

[Mn Monster]

Nice! Responses like that one are the reason RCNT is the best forum for rc troubles.

well said ! and great response ! that's why we are here ! to help and learn from each other !

 

[2revo1maxx]

Don't cut up your credit card!
You'll need it for new parts

A small paper clip works well for the idle gap.